mri of the rotator cuff

MRI of the rotator cuff

Functional considerations

• The muscles of the rotator cuff resist the upwards force of the deltoid muscle by depressing the humeral head.

Functional considerations

• The muscles of the rotator cuff compress the humeral head against the glenoid cavity, increasing joint stability

Anatomic considerations

• Any process that narrows the subacromial space may affect the rotator cuff

Anatomic considerations

• Any process that narrows the subcoracoid space may affect the rotator cuff

Pathological considerations

• Exagerated tensile forces leads to failure at:– Musculotendinous junction– Tendon insertion to bone– In bone

Pathological considerations

• In presence of tendon degeneration excessive tensile forces may lead to failure within the tendon itself

Pathological considerations

• In certain positions eg. Adduction, the avascular region is made larger

Pathological considerations

• Cuff degeneration is associated with aging

• Pathology is fibrovascular proliferation and disorganisation with no inflammation

• Not a tendonitis – tendonosis or tendonopathy

Pathological considerations

• Cuff degeneration is associated with aging

• Pathology is fibrovascular proliferation and disorganisation with no inflammation

• Not a tendonitis – tendonosis or tendonopathy

Classification of tears

• Massive tear : Full thickness tear involving more than one tendon

• Articular side• Bursal side• Intrasubstance• Low grade < 50% thickness• Medium grade 50%• High grade > 50%

Classification of tears

• Retraction• Presence or absence of muscle

atrophy– From muscle disuse related to tear– Tendon retraction with nerve injury

• Irregularity of the tendon• Articular fluid• Bursal fluid

Classification of tears

• Retraction• Presence or absence of muscle

atrophy– From muscle disuse related to tear– Tendon retraction with nerve injury

• Irregularity of the tendon• Articular fluid• Bursal fluid

Classification of tears

• Direction of tear– Vertical– Oblique– Horizontal

MR arthrography

• Standard MR inconclusive• Post op cases• Special circumstances– Posterior superior impingement– Rotator interval lesions

Cuff tears : special considerations• Rim – rent tears– With aging the inner fibres of the

tendon peel away from the greater tuberosity

– Less common than critical zone tears– Young > old

Cuff tears : special considerations• Intramuscular ganglia• Rotator interval tears• Musculotendinous tears• Laminated tears• Greater tuberosity fractures– If > 5mm displacement assoc. With cuff

tear, my require ORIF

Cuff tears : special considerations• Lesser tuberosity fractures

Treatment

• Non operative– Modification of activity– Exercises to strentghen muscles

• Operative– Open or arthroscopic– Rotator cuff repair– Subacromial decompression

Treatment

• Acromioplasty– Resect and smooth undersurface of

acromion– Resect coraco-acromial ligament– When needed, remove AC joint

osteophytes, distal clavicle

Treatment

• Repair torn tendon– Advance cuff tendons– Place and tighten tendon sutures– Screws used to reinforce repair– Arthroscopic repair

Impingement

• External– Subacromial or Subcoracoid• Tendon degeneration• Abnormality coracoacromial arch

– Altered acromial shape– ACJ OA– CAL thick– Os acromiale– GHJ instability

Impingement

• Alteration acromial morphology– Degree lateral slope: <or> 10 degrees– Shape in saittal plane• 1=straight• 2=curved• 3=angular

Impingement

• Alteration coracoid morphology– Large or laterally placed – Decrease coracohumeral distance

Impingement

• Internal impingement– Posterosuperior• Impingement of undersurface of the cuff on

the posterosuperior part of glenoid

– Anterosuperior• Impingement of BT,CAL,SGHL and

anterosuperior labrum• Associated SLAP lesion and supraspinatus

tears